EC001957 - Emergency luminaire

Hi all, I've been working on ETIM for some years in an Italy based company leader in the Emergency Luminaries sector. I struggled a lot on ETIM classification but I can't see a way to describe one main feature of our products. Most of our Emergency Luminaries are equipped with an internal battery. In case of emergency the light is supplied by the battery. You can set different level of flux / autonomy. The higher the flow, the lower the battery autonomy. For example we can configure the lamp to have Emergency Flux of 900|550|450 lumen and corresponding battery autonomy of 1.5|3|4 hour.
In ETIM I can set EV009693: Peripheral (individual battery) but I can't see any attribute suitable for my issue. Should ETIM be integrated with some more attributes ? Can these attributes be multivalue ? 
Thanks a lot for you attention, 
Simone.

Dear Simone, as far as I can see half of your problem is already solved in EC001957 - Emergency luminaire. The feature EF012518: Nominal operation time is a range-type feature, which means you can indicate that the autonomy is 1.5 to 4 hours. 

Only the feature for luminous flux is a numeric type feature, so does not allow a lumen range. That could be solved by replacing it with a range feature like EF011587: Luminous flux (not sure if it has to refer to IEC 62722-2-1). 

Finally, ETIM does not have multi-value features. A range gives the lower and upper limit, but if the values in between are not 'stepless', then you can't display that. For features like voltage, 240 V -380 V is clear to experts what the possible values are. But in your example that is different. The only option left would then be to split it up in multiple feature like "Autonomy at 900 lumen" etc., but that would not be practical. 

Conclusion, a range feature is the best solution, where the supporting documentation will give the full details. Don' t forget that ETIM's main goal is still that users find the right product easily. That they can select a luminaire with adjustable flux/autonomy is important, all the intermediate value combinations are probably not crucial in the selection phase.

If you think any changes to ETIM are necessary, please hand in a request to ETIM Italy (METEL). ETIM is an open standard and can be used by anyone for free, but change requests are only open for (local) members.